Patent literature 1 discloses that a purpose is to isotropic-pressurize a battery cell which is contained inside an exterior body to reduce internal resistance of the battery cell. As an achievement means of the purpose, patent literature 1 discloses filling and sealing low-temperature gas inside the exterior body which contains the battery cell, and sealing the exterior body. Patent literature 1 also discloses that dry air is preferable as the gas, and that the pressure of the gas when the battery is used is preferably no less than 0.01 MPa and no more than 20 MPa.
Patent literature 2 discloses that a purpose is to easily detect leakage of gas from an exterior body. As an achievement mean of the purpose, patent literature 2 discloses a technique of covering at least part of an outer surface of the exterior body with a material accommodated for detecting leakage of gas from the exterior body. In patent literature 2, the battery cell is also pressurized by filling gas inside of the exterior body.
Patent literature 3 discloses that a purpose is to cool the whole battery module uniformly. As an achievement means of the purpose, patent literature 3 discloses a technique that a cooling medium can be supplied to the inside of an exterior body so as to cool a battery module, and pressure inside the exterior body can be released depending on a temperature difference between a high temperature point and a low temperature point of the battery module. In patent literature 3, cooling air using air is disclosed as the cooling medium supplied to the inside of the exterior body. However, considering function as a cooling medium, using air containing moisture is considered to be preferable.
Patent literature 4 discloses that a purpose is to discharge moisture inside an exterior body (moisture which is attached during an all-solid-state battery manufacturing process) into an outside of the exterior body without adopting construction which decreases volume energy density of batteries. As an achievement means of the purpose, patent literature 4 discloses a technique of eliminating moisture which is contained inside the exterior body through a non-return valve by heating the exterior body from the outside of the exterior body after providing the non-return valve for the exterior body. In patent literature 4, eliminating moisture from the inside of the exterior body makes atmosphere inside the exterior body have reduced pressure.